In medium saucepan, bring 8 cups water to a boil. Add orzo; cook 8 to 10 minutes or until of desired doneness, adding carrots during last 4 minutes of cooking time.
Meanwhile, in large skillet, heat oil over medium-high heat until hot. Add onion and garlic; cook and stir 1 minute. Add mushrooms; cook and stir 2 to 3 minutes or until tender.
Drain orzo. Add cooked orzo, lemon peel, lemon juice, salt and pepper to skillet; mix well. Reduce heat to low; cook about 1 minute or until thoroughly heated. Stir in parsley.